Fat Joe is shown during an appearance at Weequahic High School in this January file photo.Patti Sapone/The Star-Ledger

NEWARK — One of his signature tracks is titled: "If it ain’t about money."

For rap star "Fat Joe" on Thursday, it was about the money.

The Miami Beach-based performer, whose real name is Joseph Cartagena, pleaded guilty in federal court in Newark on Thursday to failing to file income taxes on more than $3 million in earnings.

Cartagena, 42, who is no longer so fat, was charged in New Jersey because his production and touring companies are incorporated in the state.

He is the second major recording star in recent months to admit to tax fraud. Hip-hop artist Lauryn Hill of South Orange, an eight-time Grammy winner, earlier this year admitted she had not paid federal taxes on $1.8 million she earned over three years. The often reclusive performer could face up to three years in prison and at least $75,000 in fines when she is sentenced next March.

Fat Joe, a once portly rapper who climbed the charts with Ashanti with their hit "What’s Luv," owned Terror Squad Production and Miramar Music Touring, both based in Somerville.

In 2007, Cartagena earned $1.3 million in income and royalties that were paid through his companies, but admitted to U.S. Magistrate Judge Cathy Waldor yesterday that he never filed an income tax return. The next year, he took in $1.4 million, but again did not file with the Internal Revenue Service. And in 2009 and 2010, his earnings reached $1 million on which no tax returns were filed.

Assistant U.S. Attorney Joseph Mack told the court the total tax loss to the government was $718,038.

Cartagena’s attorney, Jeffrey Lichtman of New York, said there had never been an intent to deceive.

"This is a guy who had been paying his taxes for years when he was making a significant amount of money," Lichtman said. "He changed accountants and errors were made. We were in the process of addressing this when we received notice that there was a criminal investigation."

The attorney said the case was no an issue of tax evasion — a far more serious crime — but rather a failure to file returns.

Cartagena remains free but faces up to two years in prison and a $100,000 fine when he’s sentenced in April.